For many years, the art has struggled with the myriad of problems involved in divers communicating between one another underwater, or with other underwater locations or with the surface. Many proposals have been suggested and developed over the years for simplifying the communication apparatus carried by the diver, suppressing inhalation and other noises extraneous to the desired voice signals, improving the ultrasonic (radio-frequency) transmission and reception systems and component parts, and, in some instances, associating transducers, microphones and head sets with the diver's mask equipment and ancillary thereto. Illustrations of these struggles are represented, for example, by the following prior U.S. Pat. Nos.: 3,003,136, 3,076,174, 3,150,345, 3,164,800, 3,172,076, 3,174,129, 3,181,115-6, 3,230,500, 3,231,852, 3,267,414, 3,359,535 and 3,451,039, dealing with separate housings for electrical and electronic parts, connections and/or transducers, etc. adapted for being carried external to the diver mask and on various parts of the diver's body or even hand held; 3,790,891 and 4,154,981, dealing with alleviation of extraneous inhalation and other noises; 3,789,353, concerned with voice actuation of underwater transmission; 3,218,607, 3,347,230, 3,469,231, 4,041,441, 4,527,657, 4,839,871 and 4,885,796, treating with separate headsets, transducers and/or electronics external to or cooperative with the face mask (including, also, current apparatus of Orcatron Company of Vancouver, Canada), and, in connection with 4,123,622, for example, inside the face mask; 2,798,902, 4,418,404 and 4,432,079, concerned with single-sideband suppressed carrier improved ultrasound transmission and reception systems; and more general underwater telephone communications systems represented by 3,231,852, 3,263,207, 3,337,841, 4,039,999, 4,276,624, 4,604,737 and 4,949,072.
All of the above, and other proposals, have represented attempts to simplify apparatus and/or to improve upon the performance and user comfort and facility residing in the equipment. A promising approach before the present invention has resided in the before-mentioned attachment to the mask of a headset carrying the transducer and other components.
Despite these efforts, however, many limitations and problems still remain ---- among them, limitations inherent in separate headphones or headsets of such character that are to be diver-applied to the face mask, even assuming susceptibility to field replacement of batteries or other maintenance procedures. Such proposals, in the first place, are generally limited to face masks that are not already provided with built-in headphones; secondly, they require that the diver apply the face mask and then separately apply the headphone communication system. This is very undesirable in view of the complexity and time required and, indeed, the need for very vulnerable cable connectors for interconnecting the mask and the separate headphone communication system, even where the microphone through which the diver must speak is contained within the mask. Particularly for indutrial and military operations where there is great stress on the diver and often the need for fast operation, the concept of separate devices ---- one, a mask with microphone capability, and the other a separate communication system and interconnections ---- has proven far from desirable.
Other approaches, above-mentioned, employ a separate housing carried by the diver, as, for example, on the body, and/or also carrying a separate transducer, again connected by interconnecting cables to the mask, all having similar problems; and, additionally, as later pointed out, suffering from deleterious body shadowing of the ultrasound communication field.
Underlying the present invention, on the other hand, is the discovery that there can actually be successful total integration of the ultrasound communication system and components into the mask structure, and in a manner that enables the utilization of full face masks having headphones already provided therein for prior art types of communication systems. This integrated mask communication system concept also embodies rather novel and critical packaging concepts for the electronics and battery power sources, not only to enable ready replacement of batteries and replacement modules and the like, but, to provide minimally low profile and protrusions from the mask structure. This is important in diving operations, not just because divers are uncomfortable with protrusions, with their attendant possibility of fouling with other devices and materials in the ocean, but also to insure minimum potential shadowing or blind spot effects in the ultrasound radiation and receiving field patterns.
Subsidiary, though important, features of the total communication system-mask integration concept of the invention reside in (1) the obviating of any possibility of vulnerability, damage or disconnection of cable or other interconnections between the communication system electronics and transducer system and the microphone and earphone systems within the mask; and (2) improvements in the voice transmission through more adequate suppression of undesirable accompanying inhalation, air-hose regulator and other vibrations and sounds inherent in the diving operation. The latter result is attained by a novel microphone system, incorporated into this integrated mask-communication system, that enables voice transmission with minimum interference from the vibrations that occur in the mask system as a result of bubbles, breathing sounds and other extraneous noises that normally are transmitted by the voice microphone. This feature that enables such effective discrimination of vibrations picked up by the mask structure from the desired diver's voice sounds appears also to be applicable to other types of systems, as well, where similar interference suppression may be desired.
Still a further feature of the mask-communication integration in accordance with the invention, is the universal applicability of the construction not only to present-day masks, but also to future masks specifically designed to incorporate cavities for receiving the communication system within the mask itself as an integrated system. It has been found, moreover, that the rather deleterious effect of the relatively high positive buoyance of masks is ameliorated somewhat through the negative buoyancy weight characteristics of the integrated communication system, thus often eliminating the need for applying weights to the mask in order to resist the constant pressure of pushing the head up as a result of such mask buoyancy.